Officials in the Turkish government have blamed the Kurdistan Workers’ Party (PKK) for a recent deadly bombing in Istanbul.

“All indicators and signs regarding the attack in Istanbul yesterday point to the separatist terror organization,” President Recep Tayyip Erdogan's spokesman, Ibrahim Kalin, told a news conference on Wednesday, referring to the PKK’s role in the attack near the main tourist district, a major university and the mayor's office, which killed 11 people, including six police officers.

The PKK has yet to claim responsibility for the bombing in Istanbul although the group has carried out similar attacks in major cities across Turkey over the past months.

Four people were also killed earlier on Wednesday in a fresh bombing in the southeastern town of Midyat. More than 30 were also injured in the attack that targeted a police station.

Kalin would not comment on the attack in Midyat, a town near the Syrian border where Kurdish militants have a long record of insurgency against the government.

“The Midyat attack is very fresh and we can only make an assessment once we have all the information,” Kalin said of the attack, which reportedly damaged several buildings and triggered heavy clashes between security forces and the PKK militants.

Violence has spiraled out of control especially in southern Turkey since the government declared the collapse of ceasefire with the PKK a year ago.

Officials on Wednesday reacted to the attack in Istanbul, saying the incident will not hamper the government’s resolve in fighting the militants.

“My nation should know that the state of the Turkish Republic is strong. It is one and united no matter what the terrorist organization does,” Prime Minister Binali Yildirim said in Istanbul after visiting those wounded in the Tuesday attack.

“Whether they carry out suicide bombings in our cities, whatever methods they use, they can never wear down this nation and can never pull us back from this honorable fight,” Yildirim said.